Venting means



Oct. 16, 1945. MINER 2,386,874-

VENTING MEANS Original Filed July 10, 1940 INVENTOR //V//V6 0. M/IVEEPatented Oct. 16, 1945 VEN TIN G MEANS Irving 0. Miner, East Providence,R. I., assignor to Builders Iron Foundry, Providence, R. I., a.corporation of Rhode Island Original application July 10, 1940, SerialNo.

344,640, now Patent No. 2,357,341, dated September 5, 1944. Divided andthis application July 7, 1944, Serial No. 543,792

2 Claims.

This invention relates to improvements in venting means. More especiallyit has to do with the venting of a chamber under a piston in avertically disposed cylinder wherein liquid is to be maintained.

This application is a division of my original application, Serial No.344,640, filed July 19, 1940, which became Letters Patent No. 2,357,341on September 5, 1944.

There is shown in the appended drawing a direct-acting liquid-flowcontroller wherein the effective flow area is changed in accordance withthe variations in the pressure causing flow to the end that the rate offlow is maintained substantially constant. The controller comprises as apressure responsive element a cylinder with a piston therein movable ona vertical axis. This piston is subjected to liquid pressure on both itsupper and lower sides, and it is highly important to insure accurate andsensitive response of the piston that nothing but liquid be in thechambers on opposite sides of the piston.

It is therefore an object of this invention to provide novel ventingmeans for the chamber under the piston to the end that it may initiallybe freed of all gas and will thereafter be subject only to liquidpressure.

The best mode in which I have contemplated applying the principles of myinvention is shown in the accompanying drawing but this is to be takenas merely illustrative because it is intended that the patent shallcover by suitable expression in the appended claims whatever features ofpatentable novelty exist in the apparatus disclosed.

In the accompanying drawing:

Fig. 1 is an elevation of a controller with its associated cylinder andpiston shown in medial section and disclosing my novel venting means;and

Fig. 2 is an enlarged view of certain of the details shown in Fig.

Referring to the drawing the controller I comprises a body section l2and a discharge section M. The inlet It to the body section is connectedto a source of supply (not shown) and the outlet I8 from the dischargesection is connected to a discharge line (also not shown) in which it isdesired that the rate of flow shall be maintained substantiallyconstant. Between the inlet and the outlet the controller embraces aVenturi shaped passage or othe means for efiecting a difierential ofpressure in the line of flow. The rate of flow through the controllerand consequently in the discharge line is regulated by varying theeffective flow area of the flow passage beyond the pressure differentialmeans. The details of the particular controller herein shown forillustrative purpose will be found shown in my aforesaid Letters Patent.Sufiice it to say, that the elfective flow area is changed by meansassociated with a horizontal shaft 20 which extends outside the bodyIZand has secured thereto a grooved pulley 22. Around this pulley is acable 24 which forms a connection between a balance beam 26 at the topof the controller and a tubular piston rod 28 extending within acylinder 38 at the bottom of the controller.

Thisv cylinder has a base member 30a and a cover member 30b boltedthereto. Between these two members of the cylinder is clamped the upperedge of a diaphragm 32, made of rubber or other suitable pliablematerial, the lower edge of which is secured to the upper edge of anupstanding skirt 34a of a piston 34. When the piston is in its uppermostposition with the top edge of the skirt resting against the cover member(as indicated in dotted outline in Fig. 1) the diaphragm lies downwardalong the outer face of the skirt to close by its bottom edge and thenacross the space between the skirt and the cylinder wall, whence itextends along the inner surface of the cylinder to its clamped upperedge. As the piston moves downward the diaphragm progressively transfersfrom the side of the skirt to the wall of the cylinder until the pistonreaches its lowermost position as seen in full lines in Fig. 1. Thus thechamber 36 above the piston is maintained separate from the chamber 38below the piston at all times, and both chambers should be filled withliquid taken from the flow passage through the controller.

The upper chamber 36, above the piston, is connected by a pipe 31 to theinlet end l6 of the body. where the flow area is large or where thepressure is relatively high. The lower chamber 38, under the piston, isconnected by a pipe 40 to the controller at a point where the flow areais small or the pressure is relatively low. Thus the liquid in the lowerchamber is always below that of the upper chamber Whenever flow istaking place. To overcome this differential of pressure, the weights 42and 44 on the balance beam 26 may be so adjusted that the piston will beheld in some intermediate position so long as the desired rate of flowis maintained. If this changes, then the resulting change in theaforesaid differential of pressure will cause the piston to move upwardor downward to alter the means which change the effective flow area,thereby restoring the desired rate of flow.

It is important that both chambers 36 and 38 on opposite sides of thepiston be filled with liquid and not contain any gas as the presence ofthe latter affects the sensitiveness of "the pressure responsive meansand may also cause inaccurate operation of this means. The upper chamber36 may be easily vented by the usual and simple vent cock 46 screwedinto the cover 30b. It is not so simple a matter, however, to insureventing of the lower chamber 38, and. so myimprovements are directed tothat end. V

The piston 34 has a plate portion 34b that is in clined from its outeredge, near the bottom of the skirt, to a hub 34c at the center of theplate. Below this hub (see Fig. 2), in the lower side of the plate is arecess 3401 having separated outstanding bearing lugs 34c providingbearing surfaces for a nut 48 which is screwed onto the lower end of thepiston rod 28. The latter is tubular, extends upward through a stuflingbox 50in the cover of the cylinder, and is'secured' to a connectionblock 52 to which is also attached the cable 24. This block 52 is boredto provide a passageway from the'hollow 28a of the tubular piston 28 toa relief cook 54 screwed into the block;

When the liquid is introduced to the lower chamber 38 through thepipe'40 the valve 58 in pipe '31 is closedand the upper cook 46 is opento insure that the piston will rise to its highest point. Then the cook54 is opened, and all the air or gas in the chamber 38 Wi11,'by virtueof the inclination of the plate portion 341), the recess 34d, and ports28?) located in the piston rod near the'top of the recess, pass into thehollow of the piston rod and escape by way of'the cock 54;

When liquid starts to come out the cock 54 is 7 closed and thus it iscertain that only liquid is present in the lower chamber 38.' Liquid isnext introduced to the upper'cha'mber 38 by opening valve 58 and thisliquid will force all the air or gas in this chamber out through thecock 46, after which the latter is closed. Thus both chambers above andbelow the piston are freed of all gas or air.

Although the cylinder and piston herein shown employ a diaphragm betweenthem, this is not an essential arrangement and my improved venting meanswould be just as applicable if the piston had the usual running fitwith-the wall of the cylinder. The structural features of myimprovements are the inclined face on the bottom of the piston, thecentral recess, the ports into a tubular piston rod, and the cockconnected with the tubular passage of the rod outside the confines ofthe cylinder.

I claim:

1. Means for venting the space below a piston movable in a verticallydisposed cylinder, comprising the said piston, a surface on the bottomof the piston inclined toward its axis, a recess in the said surface atsaid axis, separated bearing lugs depending from said recessed surface,a tubular piston rod projecting through the piston and secured theretoby a nut threaded on the rod and seating on said lugs, the said rodextending upwardthrough the cylinder having a passage leading from saidrecess to outside the cylinder, and means in the piston rod outside thecylinder for effecting the opening or closing of said passage.

2. Means for venting the spacebelow a piston movable in a verticallydisposed cylinder comprising a piston having a bottom surface inclinedtoward the axis of the piston and terminating in a recess at said axis,separated bearing lugs depending from said recessed surface, a tubularpiston rod connected to said piston by a nut threaded on the rod andseating on said lugs, said rod extending through the piston having portsin the wall of the rod opposite said lugs for connecting the space ofthe recess with a passage in the piston rod that extends to outside thecylinder, and means on the piston outside the cylinder for effecting theopening or closing of said passage.

IRVING O. MINER.

